Does God command revenge or forgiveness?

1. According to book of Numbers 31, God commanded Moses to revenge, in the same time, we see Our Lord Jesus teaches us to forgive and love our enemies, what the difference? 2. In chapter 11 we read that God command to burn the cities with fire, where was His mercy? Read vs 10 10 All their cities in the places where they lived, and all their encampments, they burned with fire, 3- Why did God ask to kill women and children?  4- Why did he command to spare (save) the unmarried women? 5- Was it right to enslave those people? 6-What is the Christians’ view on slavery? 7- How we understand that in the light of what Paul said in Glations 3: 28 28 There is neither Jew nor Greek, there is neither slave[g] nor free, there is no male and female, for you are all one in Christ Jesus.